On Fri, Feb 07, 2020 at 05:35:51PM -0800, Daniel Rosenberg wrote: > This adds support for encryption with casefolding. > > Since the name on disk is case preserving, and also encrypted, we can no > longer just recompute the hash on the fly. Additionally, to avoid > leaking extra information from the hash of the unencrypted name, we use > siphash via an fscrypt v2 policy. > > The hash is stored at the end of the directory entry for all entries > inside of an encrypted and casefolded directory apart from those that > deal with '.' and '..'. This way, the change is backwards compatible > with existing ext4 filesystems. > > Signed-off-by: Daniel Rosenberg <drosen@xxxxxxxxxx> > --- > Documentation/filesystems/ext4/directory.rst | 27 ++ > fs/ext4/dir.c | 27 +- > fs/ext4/ext4.h | 64 +++- > fs/ext4/hash.c | 24 +- > fs/ext4/ialloc.c | 5 +- > fs/ext4/inline.c | 41 +-- > fs/ext4/namei.c | 291 +++++++++++++------ > fs/ext4/super.c | 6 - > 8 files changed, 343 insertions(+), 142 deletions(-) How was this tested? I tried it (using a patched version of 'mke2fs' that allows the encrypt and encoding options to be combined), and I immediately got an ext4 error about a bad directory entry: ~/e2fsprogs/misc/mke2fs -F -t ext4 -O encrypt -E encoding=utf8 /dev/vdb mount /dev/vdb /mnt fscrypt setup /mnt mkdir /mnt/dir # (assumes /etc/fscrypt.conf contains policy_version 2) echo hunter2 | fscrypt encrypt /mnt/dir --quiet --source=custom_passphrase --name=dir chattr +F /mnt/dir echo contents > /mnt/dir/file umount /mnt mount /dev/vdb /mnt ls /mnt/dir/ [ 391.292067] EXT4-fs error (device vdb): htree_dirblock_to_tree:1038: inode #8193: block 4251: comm ls: bad entry in directory: directory entry too close to block end - offset=80, inode=18, rec_len=4004, lblk=0, size=4096
